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BACKGROUND/OBJECTIVES: Capsinoids are potential antioxidant agents capable of reducing oxidative damage and the resulting complications triggered by obesity. Thus, this study aimed to investigate the effects of capsinoids on adiposity and biomarkers of cardiac oxidative stress in obese rats induced by a high-fat diet. METHODS: Male Wistar rats were exposed to a high-fat diet for 27 consecutive weeks. After the characterization of obesity (week 19), some of the obese animals began to receive capsinoids (10 mg/kg/day) by orogastric gavage. Adiposity and comorbidities were assessed. In the heart, remodeling, injury, and biomarkers of oxidative stress were determined. RESULTS: The treatment did not reduce obesity-induced adiposity but was efficient in reducing cholesterol levels. Capsinoid treatment did not cause a difference in heart and LV mass, despite having reduced troponin I concentrations. Furthermore, capsinoids did not reduce the increase in the advanced oxidation of protein products and carbonylated proteins caused by obesity in cardiac tissue. In addition, obese rats treated with capsinoids presented high levels of malondialdehyde and greater antioxidant enzyme activity compared to untreated obese rats. CONCLUSIONS: In conclusion, treatment with capsinoids increases antioxidative enzyme activity and prevents obesity-induced cardiac injury without positively modulating body fat accumulation and cardiac oxidative biomarkers.
Assuntos
Adiposidade , Antioxidantes , Biomarcadores , Dieta Hiperlipídica , Obesidade , Estresse Oxidativo , Ratos Wistar , Animais , Masculino , Obesidade/complicações , Obesidade/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Biomarcadores/sangue , Biomarcadores/metabolismo , Antioxidantes/farmacologia , Dieta Hiperlipídica/efeitos adversos , Ratos , Adiposidade/efeitos dos fármacos , Miocárdio/metabolismo , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/metabolismo , Extratos Vegetais/farmacologia , Traumatismos Cardíacos/prevenção & controle , Traumatismos Cardíacos/metabolismo , Traumatismos Cardíacos/etiologia , Malondialdeído/metabolismoRESUMO
High-intensity interval training (HIIT) has shown significant results in addressing adiposity and risk factors associated with obesity. However, there are no studies that investigate the effects of HIIT on contractility and intracellular Ca2+ handling. The purpose of this study was to explore the impact of HIIT on cardiomyocyte contractile function and intracellular Ca2+ handling in rats in which obesity was induced by a saturated high-fat diet (HFD). Male Wistar rats were initially randomized into a standard diet and a HFD group. The experimental protocol spanned 23 weeks, comprising the induction and maintenance of obesity (15 weeks) followed by HIIT treatment (8 weeks). Performance was assessed using the maximum oxygen consumption test ( V Ì O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{max}}}}$ ). Evaluation encompassed cardiac, adipose and skeletal muscle histology, as well as contractility and intracellular Ca2+ handling. HIIT resulted in a reduction in visceral area, an increase in V Ì O 2 max ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{max}}}}$ , and an augmentation of gastrocnemius fibre diameter in obese subjects. Additionally, HIIT led to a decrease in collagen fraction, an increase in percentage shortening, and a reduction in systolic Ca2+/percentage shortening and systolic Ca2+/maximum shortening rates. HIIT induces physiological cardiac remodelling, enhancing the contractile function of cardiomyocytes and improving myofilament sensitivity to Ca2+ in the context of obesity. This approach not only enhances cardiorespiratory and physical performance but also reduces visceral area and prevents interstitial fibrosis.
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Cálcio , Treinamento Intervalado de Alta Intensidade , Contração Miocárdica , Miócitos Cardíacos , Miofibrilas , Obesidade , Condicionamento Físico Animal , Ratos Wistar , Animais , Masculino , Obesidade/fisiopatologia , Obesidade/metabolismo , Obesidade/terapia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/fisiologia , Cálcio/metabolismo , Condicionamento Físico Animal/fisiologia , Ratos , Treinamento Intervalado de Alta Intensidade/métodos , Contração Miocárdica/fisiologia , Miofibrilas/metabolismo , Dieta Hiperlipídica , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Consumo de Oxigênio/fisiologiaRESUMO
INTRODUCTION: Despite strong evidences supporting the protective role of exercise against stress-induced repercussions, the literature remains inconclusive regarding metabolic aspects. Therefore, this study aimed to evaluate the effect of Physical Training (PT) by swimming on the metabolic parameters of rats subjected to restraint stress. METHODS: Wistar rats (n = 40) were divided into four groups: Control (C), Trained (T), Stressed (S), and Trained/Stressed (TS). The restraint stress protocol involved confining the animals in PVC pipes for 60 minutes/day for 12 weeks. Concurrently, the swimming PT protocol was performed without additional load in entailed sessions of 60 minutes conducted five days a week for the same duration. The following parameters were analyzed: fitness progression assessed by the physical capacity test, body mass, serum level of glucose, triglyceride, cholesterol and corticosterone, as well as glycemic tolerance test, evaluated after glucose administration (2 g/kg, i.p.). RESULTS: Trained groups (T and TS) exhibited enhanced physical capacity (169 ± 21 and 162 ± 22% increase, respectively) compared to untrained groups (C: 9 ± 5 and S: 11 ± 13% increase). Corticosterone levels were significantly higher in the S group (335 ± 9 nmoL/L) compared to C (141 ± 3 nmoL/L), T (174 ± 3 nmoL/L) and TS (231 ± 7 nmoL/L), which did not differ from each other. There were no significant changes in serum glucose, cholesterol, and triglyceride levels among the groups. However, the glycemic curve after glucose loading revealed increased glycemia in the S group (area under curve 913 ± 30 AU) but the TS group exhibited values (673 ± 12 AU) similar to the groups C (644 ± 10 AU) and T (649 ± 9 AU). CONCLUSION: Swimming-based training attenuated stress-induced corticosterone release and prevented glucose intolerance in rats, reinforcing the importance of exercise as a potential strategy to mitigate the pathophysiological effects of stress.
Assuntos
Glicemia , Corticosterona , Condicionamento Físico Animal , Ratos Wistar , Restrição Física , Estresse Psicológico , Natação , Animais , Condicionamento Físico Animal/fisiologia , Masculino , Corticosterona/sangue , Glicemia/análise , Natação/fisiologia , Estresse Psicológico/metabolismo , Colesterol/sangue , Ratos , Triglicerídeos/sangue , Fatores de Tempo , Teste de Tolerância a Glucose , Distribuição Aleatória , Metaboloma/fisiologiaRESUMO
BACKGROUND/OBJECTIVES: Myocardial infarction (MI) frequently leads to cardiac remodeling and failure with impaired life quality, playing an important role in cardiovascular deaths. Although physical exercise is a well-recognized effective non-pharmacological therapy for cardiovascular diseases, the effects of strength training (ST) on the structural and functional aspects of cardiac remodeling need to be further documented. In this study, we aimed to investigate the role of a linear block ST protocol in the rat model of MI. METHODS AND RESULTS: After 6 weeks of MI induction or sham surgery, male adult rats performed ST for the following 12 weeks. The ladder-based ST program was organized in three mesocycles of 4 weeks, with one load increment for each block according to the maximal carrying load test. After 12 weeks, the infarcted-trained rats exhibited an increase in performance, associated with reduced cardiac hypertrophy and pulmonary congestion compared with the untrained group. Despite not changing MI size, the ST program partially prevented cardiac dilatation and ventricular dysfunction assessed by echocardiography and hemodynamics, and interstitial fibrosis evaluated by histology. In addition, isolated cardiac muscles from infarcted-trained rats had improved contractility parameters in a steady state, and in response to calcium or stimuli pauses. CONCLUSIONS: The ST in infarcted rats increased the capacity to carry mass, associated with attenuation of cardiac remodeling and pulmonary congestion with improving cardiac function that could be attributed, at least in part, to the improvement of myocardial contractility.
Assuntos
Insuficiência Cardíaca , Infarto do Miocárdio , Treinamento Resistido , Humanos , Ratos , Masculino , Animais , Treinamento Resistido/métodos , Remodelação Ventricular , Ratos Wistar , Insuficiência Cardíaca/tratamento farmacológico , Miocárdio/patologia , Infarto do Miocárdio/tratamento farmacológico , Cardiomegalia , ColágenoRESUMO
Abstract Introduction: Despite strong evidences supporting the protective role of exercise against stress-induced repercussions, the literature remains inconclusive regarding metabolic aspects. Therefore, this study aimed to evaluate the effect of Physical Training (PT) by swimming on the metabolic parameters of rats subjected to restraint stress. Methods: Wistar rats (n = 40) were divided into four groups: Control (C), Trained (T), Stressed (S), and Trained/Stressed (TS). The restraint stress protocol involved confining the animals in PVC pipes for 60 minutes/day for 12 weeks. Concurrently, the swimming PT protocol was performed without additional load in entailed sessions of 60 minutes conducted five days a week for the same duration. The following parameters were analyzed: fitness progression assessed by the physical capacity test, body mass, serum level of glucose, triglyceride, cholesterol and corticosterone, as well as glycemic tolerance test, evaluated after glucose administration (2 g/kg, i.p.). Results: Trained groups (T and TS) exhibited enhanced physical capacity (169 ± 21 and 162 ± 22% increase, respectively) compared to untrained groups (C: 9 ± 5 and S: 11 ± 13% increase). Corticosterone levels were significantly higher in the S group (335 ± 9 nmoL/L) compared to C (141 ± 3 nmoL/L), T (174 ± 3 nmoL/L) and TS (231 ± 7 nmoL/L), which did not differ from each other. There were no significant changes in serum glucose, cholesterol, and triglyceride levels among the groups. However, the glycemic curve after glucose loading revealed increased glycemia in the S group (area under curve 913 ± 30 AU) but the TS group exhibited values (673 ± 12 AU) similar to the groups C (644 ± 10 AU) and T (649 ± 9 AU). Conclusion: Swimming-based training attenuated stress-induced corticosterone release and prevented glucose intolerance in rats, reinforcing the importance of exercise as a potential strategy to mitigate the pathophysiologi-cal effects of stress.
RESUMO
The aim of this study was to investigate the effectiveness of supervised and unsupervised physical training programs using outdoor gym equipment on the lifestyles of elderly people. METHODS: physically independent elderly people were randomly distributed into three groups: supervised training (n: 20; ST), unsupervised training (n: 20; UT) and control (n: 20; C). The ST and UT groups completed a 12-week program, with exercises performed three times a week. The ST group underwent weekly 30 min sessions consisting of a 5 min warm-up (walking at 60% of HRmax), followed by 20 sets of 30, "monitored by a metronome with 30" of passive recovery between sets and a five-minute cool-down. The following equipment was used: elliptical, rowing, surfing and leg press. The UT group was instructed to freely attend the gym and train spontaneously using the same equipment used by ST. Lifestyle changes were evaluated using a questionnaire containing specific domains. RESULTS: no significant differences were identified in the domains for family, physical activity, nutrition, smoking, sleep, behavior, introspection, work and overall score; however, the values corresponding to the alcohol domain for the ST and UT groups were lower (p < 0.05) than the C group, remaining even lower after the 12 weeks of intervention. Time effect (p < 0.05) was found only in the ST group for the physical domains, sleep, behavior and overall score. CONCLUSION: elderly people submitted to supervised and unsupervised physical exercise programs using outdoor gym equipment present positive changes in lifestyle parameters compared to physical inactive elderly people.
Assuntos
Exercício Físico , Exercício de Aquecimento , Idoso , Humanos , Terapia por Exercício , Estilo de Vida , CaminhadaRESUMO
Aerobic exercise training (AET) has been used to manage heart disease. AET may totally or partially restore the activity and/or expression of proteins that regulate calcium (Ca2+) handling, optimize intracellular Ca2+ flow, and attenuate cardiac functional impairment in failing hearts. However, the literature presents conflicting data regarding the effects of AET on Ca2+ transit and cardiac function in rats with heart failure resulting from aortic stenosis (AoS). This study aimed to evaluate the impact of AET on Ca2+ handling and cardiac function in rats with heart failure due to AoS. Wistar rats were distributed into two groups: control (Sham; n = 61) and aortic stenosis (AoS; n = 44). After 18 weeks, the groups were redistributed into: non-exposed to exercise training (Sham, n = 28 and AoS, n = 22) and trained (Sham-ET, n = 33 and AoS-ET, n = 22) for 10 weeks. Treadmill exercise training was performed with a velocity equivalent to the lactate threshold. The cardiac function was analyzed by echocardiogram, isolated papillary muscles, and isolated cardiomyocytes. During assays of isolated papillary muscles and isolated cardiomyocytes, the Ca2+ concentrations were evaluated. The expression of regulatory proteins for diastolic Ca2+ was assessed via Western Blot. AET attenuated the diastolic dysfunction and improved the systolic function. AoS-ET animals presented an enhanced response to post-rest contraction and SERCA2a and L-type Ca2+ channel blockage compared to the AoS. Furthermore, AET was able to improve aspects of the mechanical function and the responsiveness of the myofilaments to the Ca2+ of the AoS-ET animals. AoS animals presented an alteration in the protein expression of SERCA2a and NCX, and AET restored SERCA2a and NCX levels near normal values. Therefore, AET increased SERCA2a activity and myofilament responsiveness to Ca2+ and improved the cellular Ca2+ influx mechanism, attenuating cardiac dysfunction at cellular, tissue, and chamber levels in animals with AoS and heart failure.
Assuntos
Estenose da Valva Aórtica , Insuficiência Cardíaca , Ratos , Animais , Cálcio/metabolismo , Ratos Wistar , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/terapia , Insuficiência Cardíaca/metabolismo , Miócitos Cardíacos/metabolismo , Cálcio da Dieta/metabolismo , Estenose da Valva Aórtica/metabolismo , Exercício Físico , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismoRESUMO
BACKGROUND/AIMS: Obesity resistance is associated with the complex interaction of stringent and environmental factors that confer the ability to resist mass gain and body fat deposition, even when eating high-calorie diets. Considering that there are numerous gaps in the literature on the metabolic processes that explain Obesity resistance, specifically in relation to oxidative stress, the purpose of the study was to investigate whether obesity-resistant (OR) rats develop elevated reactive oxygen species in cardiac tissue. METHODS: Wistar rats were initially randomized into two groups: a standard diet (SD) and a high-fat diet (HFD) group. The SD and HFD groups were further divided into control (C), OR, and obese prone (OP) subgroups based on body weight. This criterion consisted of organizing the animals in each group in ascending order according to body weight (BW), and the cutoff point was identified in the animals by terciles: 1) lower BW; 2) intermediate BW; and 3) higher BW. Rats were sacrificed on the 14th week, and serum and organs were collected. Nutritional assessment, food profiles, histological analysis, comorbidities, and cardiovascular characteristics were determined. RESULTS: BW showed a significant difference between the standard diet and high-fat diet groups in the 4th week of the experimental protocol, characterizing obesity. In the 4th week, after the characterization of Obesity resistance, there was a significant difference in BW between groups C, OP, and OR. The OP and OR groups showed a significant increase in caloric intake in relation to the C group. The OP group showed a significant increase in final BW, retroperitoneal fat pad mass, sum of corporal fat deposits and reactive oxygen species, in relation to groups C and OR. The area under the glycemic curve, insulin resistance index and basal glucose were elevated in the OP group in relation to the C. OP also promoted an increase in HOMA-IR when compared with C. OR rats showed a non-significant increase in insulin and HOMA-IR in OR vs. C (p = ~0.1), but no significant differences were observed between OP vs. OR for these parameters, suggesting that both groups suffered from decreased metabolic health. Total cardiac mass, left ventricular cross-sectional area, and cholesterol levels were significantly elevated in the OP and OR groups compared with the C group. CONCLUSION: A high-fat diet induces cardiac damage in obesity-resistant rodents with reduction in metabolic health.
Assuntos
Dieta Hiperlipídica , Roedores , Animais , Ratos , Peso Corporal , Dieta Hiperlipídica/efeitos adversos , Insulina , Obesidade , Ratos Wistar , Espécies Reativas de OxigênioRESUMO
AIMS: To investigate whether the obesity associated to T2DM presented cardiomyocyte myocardial contractility dysfunction due to damage in Ca2+ handling, concomitantly with increased biomarkers of oxidative stress. METHODS: Male Wistar rats were randomized into two groups: control (C): fed with standard diet; and obese (Ob) that fed a saturated high-fat. After the characterization of obesity (12 weeks), the Ob animals were submitted to T2DM induction with a single dose of intraperitoneal (i.p.) injection of streptozotocin (30 mg/kg). Thus, remained Ob rats that were characterized as to the presence (T2DMOb; n = 8) and/or absence (Ob; n = 10) of T2DM. Cardiac remodeling was measured by post-mortem morphological, isolated cardiomyocyte contractile function, as well as by intracellular Ca2+-handling analysis. RESULTS: T2DMOb presented a significant reduction of all fat pads, total body fat and adiposity index. T2DMOb group presented a significant increase in protein carbonylation and superoxide dismutase (SOD) activity, respectively. T2DMOb promoted elevations in fractional shortening (15.6 %) and time to 50 % shortening (5.8 %), respectively. Time to 50 % Ca2+ decay was prolonged in T2DMOb, suggesting a possible impairment in Ca2+recapture and/or removal. CONCLUSION: Type 2 diabetes mellitus in obesity promotes prolongation of cardiomyocyte contractile function with protein carbonylation damage and impaired Ca2+ handling.
Assuntos
Diabetes Mellitus Tipo 2 , Miócitos Cardíacos , Animais , Masculino , Ratos , Cálcio , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/metabolismo , Contração Miocárdica , Miócitos Cardíacos/metabolismo , Obesidade/metabolismo , Carbonilação Proteica , Ratos WistarRESUMO
The study examines the influence of three types of hypercaloric diets on metabolic parameters, inflammatory markers, and oxidative stress in experimental model. Male Wistar rats (n = 40) were randomized in control (C), high-sucrose (HS), high-fat (HF), and high-fat with sucrose (HFHS) for 20 weeks. Nutritional, metabolic, hormonal, and biochemical profiles, as well as histological analysis of adipose and hepatic tissues were performed. Inflammation and oxidative stress were determined. HF model caused obesity and comorbidities as glucose intolerance and arterial hypertension. In relation to hormonal and biochemical parameters, there was no significant difference between the groups. All groups showed increased deposition of fat droplets in the hepatic tissue, even though adipocyte areas were similar. Biomarkers of oxidative stress in serum and adipose tissues were similar among the groups. HF model was effective in triggering associated obesity and comorbidities in male rats, but all hypercaloric diets were unable to promote oxidative stress and inflammation.
Assuntos
Dieta da Carga de Carboidratos , Dieta Hiperlipídica , Sacarose Alimentar , Inflamação , Obesidade , Estresse Oxidativo , Animais , Masculino , Ratos , Dieta da Carga de Carboidratos/efeitos adversos , Dieta Hiperlipídica/efeitos adversos , Sacarose Alimentar/efeitos adversos , Modelos Animais de Doenças , Inflamação/etiologia , Inflamação/metabolismo , Obesidade/etiologia , Obesidade/metabolismo , Estresse Oxidativo/fisiologia , Ratos WistarRESUMO
There are evidence that obese-resistant animals are more physically active, due to a higher rate of lipid oxidation. Efficiency in such pathways can favor greater spontaneous physical activity and, consequently, less body fat deposition. The aim of study was characterizing the nutritional profile and spontaneous physical activity in the condition of Resistance to Obesity (OR). Wistar rats were randomized into standard diet (SD; n = 50) and high-fat diet (HFD; n = 50) groups, after obesity induction, were redistributed into Control (C), False-control (FC), Propensity to obesity (OP) and OR, and then spontaneous physical activity was evaluated. Analyzed parameters: body mass (BM), epididymal (EF), retroperitoneal (RF), visceral (VF) and respective summations (∑), adiposity index (AI), nutritional, morphological, biochemical and metabolic parameters and protein quantification. The comparison of the groups was performed by ANOVA one or two factors, with 5% significance adopted. OP and FC presented high final MC values compared to C and OR. OR had lower EF, RF, VF, ∑ and IA compared to OP. OR had similar values to C and higher HDL than FC and OP. In GTT, OR and C presented similar values and both were lower than OP in the 30 minutes. OP promoted higher values than C for glycemic AUC. OR had higher PPARγ content than C and OP, as well as levels similar to C for leptin and insulin. Spontaneous physical activity did not differ between groups. The results were not enough to show that OR animals have greater lipid oxidative capacity, as well as greater spontaneous physical activity.
Assuntos
Dieta Hiperlipídica , Obesidade , Animais , Dieta Hiperlipídica/efeitos adversos , Lipídeos , Obesidade/metabolismo , Obesidade/prevenção & controle , Estresse Oxidativo , Ratos , Ratos WistarRESUMO
BACKGROUND/AIMS: Oxidative stress is associated with cardiometabolic alterations, and the involvement of excess glucose and fatty acids has been demonstrated in this process. Thus, the aim of this study was to investigate the effects of different hypercaloric diets on cardiac oxidative stress. METHODS: Wistar rats were randomized into four groups: control (C), high-sucrose (HS), high-fat (HF), and high-fat with sucrose (HFS). Nutritional assessment, food profiles, histological analysis, comorbidities, and cardiovascular characteristics were determined. Cardiac oxidative stress was analyzed by malondialdehyde (MDA) and carbonylated proteins, and the cardiac protein expression levels of type 1 angiotensin receptor (AT-1), nicotinamide adenine dinucleotide phosphate oxidase 2 (Nox2), superoxide dismutase (SOD 1 e 2), glutathione peroxidase (GPX), and catalase (CAT) were determined by western blot. RESULTS: The HF group showed an increase in adiposity; however, it did not present adipocyte hypertrophy and comorbidities. Cardiac MDA and carbonylated protein levels were higher in the HF and HFS compared with the C group. The levels of oxidant and antioxidant proteins showed no difference between the groups. CONCLUSION: HF and HFS dietary interventions promoted cardiac oxidative stress, in the presence and absence of obesity, respectively. However, this process was neither mediated by the pro-oxidants AT1 and Nox2, nor by the quantitative reduction of antioxidant enzymes.
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Dieta Hiperlipídica/efeitos adversos , Sacarose Alimentar/efeitos adversos , Cardiopatias/metabolismo , NADPH Oxidase 2/metabolismo , Obesidade/metabolismo , Estresse Oxidativo , Animais , Dieta da Carga de Carboidratos/efeitos adversos , Cardiopatias/etiologia , Masculino , Obesidade/etiologia , Oxirredução , Ratos WistarRESUMO
Digoxin is a cardiotonic that increases the cardiac output without causing deleterious effects on heart, as well as improves the left ventricular performance during physical exercise. We tested whether the association between chronic digoxin administration and aerobic interval training (AIT) promotes beneficial cardiovascular adaptations by improving the myocardial contractility and calcium (Ca2+) handling. Male Wistar rats were randomly assigned to sedentary control (C), interval training (T), sedentary digoxin (DIGO) and T associated to digoxin (TDIGO). AIT was performed on a treadmill (1h/day, 5 days/week) for 60 days, consisting of successive 8-min periods at 80% and 20% of VO2máx for 2 min. Digoxin was administered by orogastric gavage for 60 days. Left ventricle samples were collected to analysis of Ca2+ handling proteins; contractility and Ca2+ handling were performed on isolated cardiomyocytes. TDIGO group had a greater elevation in fractional shortening (44%) than DIGO, suggesting a cardiomyocyte contractile improvement. In addition, T or TDIGO groups showed no change in cardiomyocytes properties after Fura2-acetoxymethyl ester, as well as in sarcoplasmic reticulum Ca2+-ATPase (SERCA2a), phospholamban and calcineurin expressions. The main findings indicate that association of digoxin and aerobic interval training improved the cardiomyocyte contractile function, but these effects seem to be unrelated to Ca2+ handling.
Assuntos
Cálcio/metabolismo , Cardiotônicos/farmacologia , Digoxina/farmacologia , Treinamento Intervalado de Alta Intensidade/métodos , Contração Miocárdica/fisiologia , Miócitos Cardíacos/fisiologia , Animais , Calcineurina/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Cardiotônicos/administração & dosagem , Digoxina/administração & dosagem , Teste de Esforço/métodos , Ventrículos do Coração/metabolismo , Ácido Láctico/sangue , Masculino , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Condicionamento Físico Animal/métodos , Distribuição Aleatória , Ratos , Ratos Wistar , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Comportamento SedentárioRESUMO
Despite the strong evidence on the cardiac and renal damages after chronic exposure to cigarette smoke, there is a paucity of data on its short-term effects. The study evaluated the short-term effects of cigarette smoking on left ventricular (LV) remodeling, in vitro myocardial and renal function. Female Wistar rats were randomized to control (C) and cigarette smoking rats for eight weeks. Physical capacity was assessed using an adapted model of exhaustive swim; left ventricle (LV) morphology and function were also evaluated. Renal function was assessed by creatinine clearance and urine protein. The in vitro myocardial performance was analyzed in isolated papillary muscles. Rats exhibited reduced physical capacity after short-term cigarette smoking. Although there was no change on LV function, reduced chamber diameter was found in the smoking group associated with an increased LV wall thickness. There was augmented cardiac mass compared to C that was confirmed by increased cardiomyocyte nucleus volume, but in vitro myocardial performance and renal function were unchanged. A short-term cigarette smoking induces cardiac remodeling without abnormalities in function. The smoking group still preserved renal function and in vitro myocardial performance. However, the reduced physical capacity may suggest an impairment of the cardiac reserve.
Assuntos
Núcleo Celular/efeitos dos fármacos , Miocárdio/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Fumaça/efeitos adversos , Função Ventricular Esquerda/efeitos dos fármacos , Remodelação Ventricular , Animais , Pressão Sanguínea , Núcleo Celular/metabolismo , Fumar Cigarros , Ecocardiografia Doppler , Feminino , Hemodinâmica , Técnicas In Vitro , Testes de Função Renal , Infarto do Miocárdio/fisiopatologia , Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Ratos , Ratos Wistar , Recidiva , Função Ventricular Esquerda/fisiologiaRESUMO
Resistance training (RT) improves the cardiomyocyte calcium (Ca2+) cycling during excitation-contraction coupling. However, the role of RT in cardiomyocyte contractile function associated with Ca2+ handling in obesity is unclear. Wistar rats were distributed into four groups: control, sedentary obese, control plus RT, and obesity plus RT. The 10-wk RT protocol was used (4-5 vertical ladder climbs, 60-second interval, 3× a week, 50-100% of maximum load). Metabolic, hormonal, cardiovascular and biochemical parameters were determined. Reduced leptin levels, epididymal, retroperitoneal and visceral fat pads, lower body fat, and adiposity index were observed in RT. Obesity promoted elevation of collagen, but RT did not promote modifications of LV collagen in ObRT. RT induced elevation in maximum rates of contraction and relaxation, and reduction of time to 50% relaxation. ObRT group did not present improvement in the cardiomyocyte contractile function in comparison to Ob group. Reduced cardiac PLB serine16 phosphorylation (pPLB Ser16) and pPLB Ser16/PLB ratio with no alterations in sarcoplasmic reticulum Ca2+ ATPase (SERCA2a) and phospholamban (PLB) expression were observed in Ob groups. Resistance training improved body composition reduced fat pads and plasma leptin levels but did not promote positive alterations in cardiomyocyte contractile function, Ca2+ handling and phospholamban phosphorylation.
Assuntos
Gordura Intra-Abdominal/metabolismo , Contração Miocárdica/fisiologia , Obesidade/terapia , Treinamento Resistido , Animais , Cálcio/metabolismo , Humanos , Gordura Intra-Abdominal/patologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Miócitos Cardíacos/fisiologia , Obesidade/fisiopatologia , Condicionamento Físico Animal , RatosRESUMO
Several diseases are associated with excess of adipose tissue, and obesity is considered an independent risk factor for the development of cardiac remodeling and heart failure. Dietary aspects have been studied to elucidate the mechanisms involved in these processes. Thus, the purpose was the development and characterization of an obesity experimental model from hypercaloric diets, which resulted in cardiac remodeling and predisposition to heart failure. Thirty- day-old male Wistar rats (n = 52) were randomized into four groups: control (C), high sucrose (HS), high-fat (HF) and high-fat and sucrose (HFHS) for 20 weeks. General characteristics, comorbidities, weights of the heart, left (LV) and right ventricles, atrium, and relationships with the tibia length were evaluated. The LV myocyte cross sectional area and fraction of interstitial collagen were assayed. Cardiac function was determined by hemodynamic analysis and the contractility by cardiomyocyte contractile function. Heart failure was analyzed by pulmonary congestion, right ventricular hypertrophy, and hemodynamic parameters. HF and HFHS models led to obesity by increase in adiposity index (C = 8.3 ± 0.2% vs. HF = 10.9 ± 0.5%, HFHS = 10.2 ± 0.3%). There was no change in the morphological parameters and heart failure signals. HF and HFHS caused a reduction in times to 50% relaxation without cardiomyocyte contractile damage. The HS model presented cardiomyocyte contractile dysfunction visualized by lower shortening (C: 8.34 ± 0.32% vs. HS: 6.91 ± 0.28), as well as the Ca2+ transient amplitude was also increased when compared to HFHS. In conclusion, the experimental diets based on high amounts of sugar, lard or a combination of both did not promote cardiac remodeling with predisposition to heart failure under conditions of obesity or excess sucrose. Nevertheless, excess sucrose causes cardiomyocyte contractility dysfunction associated with alterations in the myocyte sensitivity to intracellular Ca2+.
Assuntos
Dieta da Carga de Carboidratos/efeitos adversos , Sacarose Alimentar/administração & dosagem , Sacarose Alimentar/efeitos adversos , Insuficiência Cardíaca/etiologia , Animais , Sinalização do Cálcio , Colágeno/metabolismo , Dieta Hiperlipídica/efeitos adversos , Gorduras na Dieta/administração & dosagem , Gorduras na Dieta/efeitos adversos , Modelos Animais de Doenças , Ingestão de Energia , Insuficiência Cardíaca/patologia , Insuficiência Cardíaca/fisiopatologia , Masculino , Modelos Cardiovasculares , Contração Miocárdica , Miocárdio/metabolismo , Miocárdio/patologia , Miócitos Cardíacos/fisiologia , Obesidade/complicações , Obesidade/patologia , Obesidade/fisiopatologia , Ratos , Ratos Wistar , Remodelação Ventricular/fisiologiaRESUMO
Severe food restriction (FR) impairs cardiac performance, although the causative mechanisms remain elusive. Since proteins associated with calcium handling may contribute to cardiac dysfunction, this study aimed to evaluate whether severe FR results in alterations in the expression and activity of Ca2+-handling proteins that contribute to impaired myocardial performance. Male 60-day-old Wistar-Kyoto rats were fed a control or restricted diet (50% reduction in the food consumed by the control group) for 90 days. Body weight, body fat pads, adiposity index, as well as the weights of the soleus muscle and lung, were obtained. Cardiac remodeling was assessed by morphological measures. The myocardial contractile performance was analyzed in isolated papillary muscles during the administration of extracellular Ca2+ and in the absence or presence of a sarcoplasmic reticulum Ca2+-ATPase (SERCA2a) specific blocker. The expression of Ca2+-handling regulatory proteins was analyzed via Western Blot. Severe FR resulted in a 50% decrease in body weight and adiposity measures. Cardiac morphometry was substantially altered, as heart weights were nearly twofold lower in FR rats. Papillary muscles isolated from FR hearts displayed mechanical dysfunction, including decreased developed tension and reduced contractility and relaxation. The administration of a SERCA2a blocker led to further decrements in contractile function in FR hearts, suggesting impaired SERCA2a activity. Moreover, the FR rats presented a lower expression of L-type Ca2+ channels. Therefore, myocardial dysfunction induced by severe food restriction is associated with changes in the calcium-handling properties in rats.
Assuntos
Sinalização do Cálcio , Cálcio/metabolismo , Restrição Calórica , Cardiopatias/etiologia , Desnutrição/complicações , Mitocôndrias Cardíacas/metabolismo , Contração Miocárdica , Miócitos Cardíacos/metabolismo , Músculos Papilares/metabolismo , Adiposidade , Animais , Canais de Cálcio Tipo L/metabolismo , Modelos Animais de Doenças , Cardiopatias/metabolismo , Cardiopatias/patologia , Cardiopatias/fisiopatologia , Masculino , Desnutrição/metabolismo , Desnutrição/patologia , Desnutrição/fisiopatologia , Mitocôndrias Cardíacas/patologia , Miócitos Cardíacos/patologia , Músculos Papilares/patologia , Músculos Papilares/fisiopatologia , Ratos Endogâmicos WKY , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Redução de PesoRESUMO
Experimental studies show that the unsaturated high-fat diet-induced obesity promotes vascular alterations characterized by improving the endothelial L-arginine/Nitric Oxide (NO) pathway. Leptin seems to be involved in this process, promoting vasodilation via increasing NO bioavailability. The aim of this study was to test the hypothesis that unsaturated high-fat diet-induced obesity does not generate endothelial dysfunction via increasing the vascular leptin/Akt/eNOS signaling. Thirty-day-old male Wistar rats were randomized into two groups: control (C) and obese (Ob). Group C was fed a standard diet, while group Ob was fed an unsaturated high-fat diet for 27 weeks. Adiposity, hormonal and biochemical parameters, and systolic blood pressure were observed. Concentration response curves were performed for leptin or acetylcholine in the presence or absence of Akt and NOS inhibitor. Our results showed that an unsaturated high-fat diet promoted a greater feed efficiency (FE), elevation of body weight and body fat (BF), and an adiposity index, characterizing a model of obesity. However, comorbidities frequently associated with experimental obesity were not visualized, such as glucose intolerance, dyslipidemia and hypertension. The evaluation of the endothelium-dependent relaxation with acetylcholine showed no differences between the C and Ob rats. After NOS inhibition, the response was completely abolished in the Ob group, but not in the C group. Furthermore, Akt inhibition completely blunted vascular relaxation in the C group, but not in the Ob group, which was more sensitive to leptin-induced vascular relaxation. L-NAME incubation abolished the relaxation in both groups at the same level. Although Akt inhibitor pre-incubation reduced the leptin response, group C was more sensitive to its effect. In conclusion, the high-unsaturated fat diet-induced obesity improved the vascular reactivity to leptin and does not generate endothelial dysfunction, possibly by the increase in the vascular sensitivity to leptin and increasing NO bioavailability. Moreover, our results suggest that the increase in NO production occurs through the increase in NOS activation by leptin and is partially mediated by the Akt pathway.
RESUMO
BACKGROUND: Dietary interventions in rodents can induce an excess of adipose tissue and metabolic disorders that resemble human obesity. Nevertheless, these approaches are not standardized, and the phenotypes may vary distinctly among studies. The aim of this study was to investigate the effects of different dietary interventions on nutritional, metabolic, biochemical, hormonal, and cardiovascular profiles, as well as to add to development and characterization of an experimental model of obesity. METHODS: Male Wistar rats were randomized into four groups: control diet (C), high-sugar (HS), high-fat (HF), or high-sugar and high-fat (HFHS). Weekly measurements of body weight, adiposity, area under the curve (AUC) for glucose, blood pressure (BP) and serum triglycerides, total cholesterol level, and leptin were performed. RESULTS: HF and HFHS models were led to obesity by increases in adipose tissue deposition and the adiposity index. All hypercaloric diets presented systolic BP increases. In addition, the AUC for glucose was greater in HF and HFHS than in C, and only the HF group presented hyperleptinemia. CONCLUSIONS: HF and HFHS diet approaches promote obesity and comorbidities, and thus represent a useful tool for studying human obesity-related disorders. By contrast, the HS model did not prove to be a good model of obesity.
Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Gorduras na Dieta , Açúcares da Dieta , Obesidade/etiologia , Adiposidade , Ração Animal , Animais , Biomarcadores/sangue , Glicemia/metabolismo , Pressão Sanguínea , Colesterol/sangue , Modelos Animais de Doenças , Ingestão de Energia , Nível de Saúde , Leptina/sangue , Masculino , Valor Nutritivo , Obesidade/metabolismo , Obesidade/fisiopatologia , Ratos Wistar , Fatores de Tempo , Triglicerídeos/sangue , Aumento de PesoRESUMO
Introdução: A senescência provoca alterações nas características morfofuncionais do indivíduo, bem como uma série de desordens nutricionais como sobrepeso e obesidade. Objetivo: O estudo avaliou a prevalência de sobrepeso e obesidade em idosas dos Centros de Convivência para a Terceira Idade de Vitória/ES. Material e Métodos: Foi realizado estudo de campo transversal e a amostra de conveniência foi composta por 135 idosas entre 60 e 79 anos. Foram mensuradas a massa corporal, estatura e dobras cutâneas para verificação do índice de massa corpórea (IMC) e percentual de gordura corporal (%GC), respectivamente. Para a comparação das características antropométricas entre os grupos etários de idosas foi utilizado o teste "t" de Student para amostras independentes. As prevalên-cias de sobrepeso e obesidade foram analisadas por meio do teste do qui-quadrado. O nível de significância adotado foi 5%. Resultados: Os resultados, com base no IMC, demonstram alta prevalência de obesidade (28% e 22% nos grupos etários de 60 a 69 e 70 a 79 anos, respectivamente) e sobrepeso (19% e 17% nos grupos etários de 60 a 69 e 70 a 79 anos, respectivamente), representando conjuntamente 42,96% de prevalência de excesso de peso na população estudada. Os resultados do %GC mostram alta prevalência de idosas agrupadas na classificação "ruim" e "muito ruim", representando 33% em ambos os grupos etários. Conclusão: O estudo mostra alta prevalência de sobrepeso e obesidade nas idosas, reforçando a necessidade de implementação de programas de reeducação alimentar e atividade física destinados à redução de gordura corporal. (AU)
Introduction: Senescence alters the morpho-functional characteristics of the individual as well as do a number of nutritional disorders, such as overweight and obesity. Objective: This study assessed the prevalence of overweight and obesity among aged women from the Community Center for the Elderly in Vitória, ES, Brazil. Materials and Method: A cross-sectional study was performed and a convenience sample was composed of 135 women aged between 60 and 79 years. Body weight, height and skinfold were recorded in order to check body mass index (BMI) and percentage of body fat (%BF), respectively. T test for independent samples was used to compare the anthropometric characteristics among age groups. The prevalence of overweight and obesity was analyzed using the chi-square test. The level of significance was 5%. Results: BMI values showed a high prevalence of obesity (28% and 22% in the age groups 60-69 and 70-79 years, respectively) and overweight (19% and 17% in the age groups 60-69 and 70 to 79 years, respectively), which consist together of an overweight prevalence of 42.96% in the studied population. The %BF results showed a high prevalence of elderly classified into the "poor" and "very poor" categories, representing 33% of the sample in both age groups. Conclusion: This study shows a high prevalence of overweight and obesity among aged women from the Community Center for the Elderly in Vitória, ES, which reinforces the need for implementation of nutritional and physical activity programs for body fat reduction. (AU)